| 摘要 |
PROBLEM TO BE SOLVED: To perfectly and exactly execute information reproduction by holding a transparent layer on a transparent substrate with information recording layers providing one thereof consisting of materials which are changed in transmittance with the prescribed temp. as the threshold. SOLUTION: This optical disk is composed of the transparent substrate 11, the first information recording layer 10, the transparent layer 19 and the second information recording layer 20. The recording layer 10 is formed as a translucent reflection layer, the recording layer 20 is composed of a first dielectric protective layer 12, a transmittance changing layer 13, a second dielectric protective layer 14, a reflection layer 15 and a third dielectric protective layer 16. The thermal conductivity characteristics of the changing layer 13 and the reflection layer 15 are adjusted by selecting the materials and thicknesses of the dielectric protective layers. A phase transition material is used for the changing layer 13 for this purpose so that the layer reversibly changes from a crystalline structure to a molten structure to prevent the occurrence a compsn. change, such as phase sepn., and segregation. Thermal burden arises in the respective layers on the circumference if the m.p. of the phase transition material of the changing layer 13 is high and, therefore, the m.p. is confined in a range of 700 to 500 deg.C and the crystallization speed thereof is confined to <=500nsec. |
